Point out the error in the program

#include<stdio.h>
int main

Point out the error in the program

#include<stdio.h>
int main()
 {
     int a=10;
     void f();
     a = f();
     printf("%d\n", a);
     return 0;
 }
 void f()
 {
     printf("Hi");
 }

2) Which of the following statements are correct about the function?

long fun(int num)
 {
     int i;
     long f=1;
     for(i=1; i<=num; i++)
         f = f * i;
     return f;
 }

3) How many times the program will print "Study 2 Online" ?

  #include<stdio.h>
  int main()
 {
     printf("Study 2 Online");
     main();
     return 0;
 }

4) Which library function returns number of seconds elapsed beyond a designated base time?

5) Which of the following statements are correct about the program?

#include<stdio.h>
int main()
 {
     printf("%p\n", main());
     return 0;
 }